CN116184329A

CN116184329A - Method and apparatus for speed and/or position sensing

Info

Publication number: CN116184329A
Application number: CN202310309869.3A
Authority: CN
Inventors: D.哈默施密特; E.科尔姆霍弗; R.拉希纳
Original assignee: Infineon Technologies AG
Current assignee: Infineon Technologies AG
Priority date: 2016-01-29
Filing date: 2017-01-26
Publication date: 2023-05-30
Also published as: US20170222738A1; US20210288725A1; CN107037426A; DE102016101595A1; US11063677B2

Abstract

Methods and apparatus for speed and/or position sensing are disclosed. Embodiments relate to a machine comprising: a movable member; transceiver circuitry configured to transmit radio signals toward the movable component and to receive reflections of the radio signals from the movable component; an evaluation circuit configured to determine a position or velocity of the movable component based at least on the received radio signal. The distance between the antenna of the transceiver circuit and the movable part is less than 5cm.

Description

Method and apparatus for speed and/or position sensing

The present application is a divisional application of the inventive patent application with application date 2017, 1-26, application number 201710057069.1 and the name "method and apparatus for speed and/or position sensing".

Technical Field

Embodiments relate to methods and apparatus for speed and/or position sensing and more particularly for highly accurate speed and/or position sensing for, for example, automotive applications.

Background

Many vehicle, industrial and consumer applications rely on magnetic sensors. Examples of such applications include speed sensing applications such as wheel speed, transmission speed (transmission speed), crankshaft and camshaft sensing. A wheel speed sensor Integrated Circuit (IC) may be used to measure the speed of each wheel and detect whether the wheel is locked during braking (ABS). This measurement result can be used as a basic input signal for an Electronic Stability Program (ESP) of the motor vehicle. For example, a magnetic angle sensor and a linear hall sensor may also be used to measure the steering angle and steering torque. The use of hall and magnetoresistive sensing elements for monolithically integrated magnetic sensors is known.

Magnetic field applications incur additional costs on the application side due to the need for pole wheels or ferromagnetic toothed wheels and reverse bias magnets. Accordingly, it is desirable to reduce sensor costs in the above-mentioned vehicle, industrial and consumer applications.

Disclosure of Invention

Embodiments of the present disclosure propose an object detection sensor that relies on radio waves to determine the position and/or velocity of a moving object and use the proposed sensor in velocity and/or angle sensing applications. In some embodiments, the distance between the transceiver and the moving object will be relatively small, e.g., in the range of millimeters (mm) or centimeters (em). Thus, the radio transceiver may generate a radio signal having only a small electric power in the microwatts (μw) range.

According to a first aspect of the present disclosure, a machine is provided. The machine includes a movable part (movable part). The machine also includes a transceiver circuit including at least one antenna. The distance between the antenna and the movable part is less than 5cm. The transceiver circuitry is configured to transmit radio signals toward the movable component and to receive reflections of the radio signals from the movable component. The machine still further includes an evaluation circuit configured to determine a position and/or velocity of the movable component based at least on the received reflected radio signal.

In some examples, the transceiver circuitry is configured to transmit radio signals having an electrical power of less than 100 μw.

In some examples, the transceiver circuit includes an antenna array, and the evaluation circuit is further configured to determine the direction of rotation of the movable component based on a combination of received signals of different antenna elements of the antenna array.

In some examples, the transceiver circuit and the evaluation circuit are integrated in a common semiconductor package or chip.

In some examples, the movable component and the transceiver circuitry are commonly disposed in a shielded enclosure.

In some examples, adjacent surface portions of the movable component are configured to alternate electromagnetic reflectivity of radio signals.

In some examples, the movable component is a rotatable movable component, and the evaluation circuit is configured to determine a rotational position or rotational speed of the movable component based at least on the received radio signal.

In some examples, the movable member includes a rotationally symmetrical cross-section in a plane perpendicular to a rotational axis of the movable member.

In some examples, the movable component is a wheel, a disc, or a shaft.

In some examples, the movable component includes a rotationally asymmetric cross-section in a plane perpendicular to a rotational axis of the movable component.

In some examples, the ratio between the smallest and largest diameter of the movable member in the plane is less than 0.9.

In some examples, the evaluation circuit is configured to determine the position or velocity of the movable component based on a change in power of the received signal or a phase difference between the transmitted and received radio signals.

In some examples, the machine is a vehicle.

According to a second aspect of the present disclosure, an integrated sensor circuit is provided. The integrated sensor circuit includes a transceiver circuit configured to transmit a radio signal having an electrical power of less than 100 μw toward a moving object and to receive a reflection of the radio signal from the moving object. The integrated sensor circuit further comprises an evaluation circuit configured to determine a position and/or a velocity of the active object based at least on the received reflected radio signal.

According to a further aspect of the present disclosure, a method for position and/or velocity sensing is provided. The method includes moving the object relative to at least one antenna of the transceiver, wherein a distance between the antenna and the moving object is (and remains) less than 5cm. The method also includes transmitting a radio signal from the transceiver toward the active object and receiving a reflection of the radio signal from the active object at the transceiver. The position and/or velocity of the object is determined based at least on the received radio signals.

In some examples, the position or velocity of the active object is determined based on a change in the power of the received signal or a phase difference between the transmitted and received radio signals.

In some examples, a radio signal having an electrical power of at most 100 μw is transmitted.

In some examples, transmitting, receiving, and determining occur in a machine, and wherein the object is a rotating component of the machine.

In some examples, the method further comprises forwarding the position or velocity to an electronic control unit of the vehicle.

In some examples, forwarding the position or velocity includes generating a signal pulse, wherein edges of the signal pulse correspond to a structure of the object.

In some examples, the object is at least one of a crankshaft, a camshaft, or an axle.

According to yet further aspects of the present disclosure, a machine is provided. The machine includes a movable member; transceiver circuitry configured to transmit radio signals toward the movable component and to receive reflections of the radio signals from the movable component; and an evaluation circuit configured to determine a position and/or a velocity of the movable component based at least on the received radio signal. The adjacent surface portions of the movable member are configured to cause or generate different magnitudes of the reflected radio signal.

In some examples, the first electromagnetic reflectivity of the radio signal of the first surface portion is different from the second electromagnetic reflectivity of the radio signal of the adjacent second surface portion.

In some examples, the first electromagnetic reflectivity differs from the second electromagnetic reflectivity by more than 5% of the first or second electromagnetic reflectivity.

In some examples, a shortest distance between a first surface portion of the movable component and an antenna of the transceiver circuit is different than a shortest distance between an adjacent second surface portion of the movable component and an antenna of the transceiver circuit.

In some examples, the shortest distance between the first surface portion and the antenna differs from the shortest distance between the adjacent second surface portion and the antenna by more than 5%.

In some examples, the distance between the antenna of the transceiver circuit and the movable part is less than 5cm.

According to yet another further aspect of the present disclosure, a machine is provided. The machine comprises a rotating movable part having a rotationally asymmetric cross section in a plane perpendicular to the axis of rotation of the movable part. The machine further includes transceiver circuitry configured to transmit a radio signal toward the movable component and to receive a reflection of the radio signal from the movable component; and an evaluation circuit configured to determine a rotational position and/or a rotational speed of the movable component based at least on the received radio signal.

Drawings

Some embodiments of the apparatus and/or method will hereinafter be described, by way of example only, with reference to the accompanying drawings, in which:

FIGS. 1a, b illustrate examples of incremental magnetic field sensing;

FIG. 2 illustrates a diagram of a sensing system according to an embodiment;

fig. 3 shows an example of an incremental speed sensor for use on a radio wave basis;

fig. 4a, b show further examples of a radio wave based sensing system using rotationally symmetric moving parts;

FIGS. 5a-c illustrate examples of radio wave based sensing systems using rotationally asymmetric movable components;

FIG. 6 illustrates a high-level flow diagram of a method for position and/or velocity sensing according to an embodiment; and

fig. 7 illustrates an example of a reflected signal associated with an example embodiment for speed sensing.

Detailed Description

Various example embodiments will now be described more fully with reference to the accompanying drawings in which some example embodiments are shown. In the drawings, the thickness of lines, layers and/or regions may be exaggerated for clarity.

Thus, while further embodiments are susceptible to various modifications and alternative forms, certain example embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but on the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure. Like numbers refer to the same or similar elements throughout the description of the figures.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements (e.g., "between …" versus "directly between …", "adjacent" versus "directly adjacent", etc.) should be interpreted in the same manner.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of further example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," "including" and/or "including," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in conjunction with the term "in" unless expressly defined otherwise herein.

Certain embodiments of the present disclosure propose to use radar systems instead of magnetic field sensors to measure rotational speed or position based on a structured target. For example, automotive radar is currently used for distance measurement in the scale range from tens of centimeters to hundreds of meters. Embodiments propose a complete new concept for speed or angle sensors currently in vehicles or other machines, which make use of measurements in the sub-centimeter or even sub-millimeter range by low-power radar sensors of low complexity. As such, this new concept can replace conventional magnetic sensors used for speed or angle sensors, thereby reducing system costs.

Magnetic delta field measurements are well established. Two example principles of magnetic sensing are shown in fig. 1a and b.

In the example of fig. 1a, a magnetic sensor 100 is used to detect the position and/or speed of a rotatable movable ferromagnetic toothed wheel or gear 110. The magnetic sensor 100 includes a reverse bias magnet 102 to generate a bias magnetic field that is affected by a moving gear 110. Further, the magnetic sensor 100 includes first and second magnetic sensor elements 104-1, 104-2 to sense a change in a bias magnetic field due to the gear 110. Examples of magnetic sensor elements are hall sensor or magnetoresistive sensor elements. The optional signal processing circuit 106 may further process the signals provided by the magnetic sensor elements 104-1, 104-2. Due to the differential arrangement of the magnetic sensor elements 104-1, 104-2, the rotational direction of the gear 110 may also be detected, for example, based on the phase difference between the signals of the first and second magnetic sensor elements 104-1, 104-2. The output signal of the magnetic sensor 100 may be fed to, for example, an Electronic Control Unit (ECU) of the vehicle.

A different setup for magnetic incremental speed/position sensing is shown in fig. 1 b. In this example, a magnetic sensor 150 is used to detect the position and/or speed of a rotatable movable magnetic encoder wheel (pole wheel) 160 comprising alternating magnetic poles in the circumferential direction. The magnetic sensor 150 includes first and second magnetic sensor elements 154-1, 154-2 to sense changes in the magnetic field originating from the rotary encoder wheel 160. Again, examples of magnetic sensor elements are hall sensor or magneto-resistive sensor elements. The optional signal processing circuitry 156 may further process the signals provided by the magnetic sensor elements 154-1, 154-2. The rotational direction of the encoder wheel 160 may also be detected due to the differential arrangement of the magnetic sensor elements 154-1, 154-2. The output signal of the magnetic sensor 150 may be fed to, for example, an Electronic Control Unit (ECU) of the vehicle.

The magnetic sensing device of fig. 1 may be used in automotive applications including angle sensing applications or speed sensing applications such as wheel speed, transmission speed, crankshaft and camshaft sensing. However, such magnetic field applications cause additional cost and/or space requirements on the application side due to the need for pole wheels or ferromagnetic toothed wheels and reverse bias magnets.

Embodiments of the present disclosure thus present a complete new concept of using radar sensors for angle and/or speed sensing applications. As will be appreciated by those having the benefit of this disclosure, in the case of radar the toothed wheel may be made simpler, for example a plastic toothed wheel or disc with a printed metal pattern that alters the reflectivity. In applications related to gearboxes or transmissions, conventional toothed wheels may be used for rotational speed sensing together with radar sensors. In contrast to magnetic sensors, these toothed wheels do not have to be ferromagnetic or have an installed reverse bias magnet.

Automotive radar is currently used for distance measurement over a large scale range d=1..200m. The price per radar system decreases rapidly and the reduction in the radar system's requirement for very short range measurements (e.g., d=1..5 mm) required for target applications will be due to reduced power consumption (-d) ^-4 ) While allowing for additional reduced costs. In addition, application changes from linear distance measurement to binary mode detection will allow for additional simplified radar system design. This indicates that the cost reduction function of the radar system for the incremental speed and position sensor should be much more aggressive than that of the magnetic sensor. Thus, a cost situation may be reached in which the replacement of the magnetic field sensor with the radar system may be initiated.

Turning now to fig. 2, a high-level block diagram of a system or machine 200 according to an embodiment is shown.

Machine 200 includes a movable component 210, transceiver circuitry 220, and evaluation circuitry 230. The transceiver circuit 220 includes transmitter and

receiver circuits

222, 224 and at least one antenna 226. The distance d between the at least one antenna 226 and the movable part 210 is less than 5cm. In certain embodiments, the distance d may be even smaller, e.g., less than 3cm, less than 1cm, or even less than 5mm. The distance d may be understood as the shortest distance between the surface portion of the movable part 210 facing the antenna 226 and the antenna 226. Transmitting and receivingThe machine circuit 220 is configured to transmit a modulated or unmodulated radio signal s towards the movable part 210 _t And receives the reflection s of the radio signal from the movable part 210 _r . The evaluation circuit 230 is configured to be based at least on the received radio signal s _r To determine the position and/or velocity of movable element 210. In some embodiments, it may also be based on the transmitted signal s _t And the received/reflected signal s _r To determine position and/or velocity.

In certain embodiments, machine 200 may be a vehicle, such as an automobile. However, those skilled in the art having the benefit of this disclosure will appreciate that machine 200 may be any machine that uses a sensor device to perform motion detection of one or more moving parts of the machine. That is, the machine 200 may also be an industrial machine, a household machine, or the like.

According to an embodiment, the transceiver circuit 220 utilizes radar principles. Radar is an object detection system that uses radio waves to determine the nature of an object. The transceiver circuit 224 emits radio waves or microwaves that are reflected in their path from the movable member 210. Receiver circuitry 222, which may be monolithically integrated with transmitter circuitry 224, receives and processes these reflected waves to determine the nature of movable element 210. Transceiver circuitry 220 may include additional analog and/or digital hardware components such as power supply circuitry, electronic oscillator circuitry, modulator circuitry, amplifier circuitry, and/or impedance matching circuitry.

Transceiver circuit 220 may be a monolithic Integrated Circuit (IC) implemented in a single semiconductor package or chip. In some embodiments, the at least one antenna and/or evaluation circuit 230 may also be a monolithically integrated structure with the transceiver circuit 220. In particular for radio signals s _t Monolithic integration of the antenna 226 may be a desirable option for high radio frequencies. In some embodiments, transceiver circuitry 220 may be configured to generate radio signals s having a radio frequency of at least 20GHz _t . In some embodiments, transceiver circuitry 220 may be configured to generate a radio frequency having at least 60GHzRadio signal s _t . Depending on the application and/or the environment, even higher frequencies may be used, such as radio frequencies above 100GHz or even above 200 GHz.

The radar sensor IC according to an embodiment may be packaged in a 2-pin package, which may be compatible with conventional magnetic sensor packages. This may lead to a conciseness (transparency) for a downstream located signal processing entity, such as an electronic control unit ECU, for example in terms of the sensor technology employed. That is, the ECU will not recognize whether it is receiving signals from a magnetic sensor or alternatively from a radar sensor. Thus, in certain embodiments, the evaluation circuit 230 may be configured to forward the position and/or velocity to the ECU of the vehicle for further processing.

Due to the relatively small distance d between the at least one antenna 226 and the movable part 210, the transceiver circuit 220 may be configured for small electrical power. For example, the transceiver circuit 220 may be configured to transmit a radio signal s having an electrical power of less than 100 μW _t . Depending on the distance d, the signal s _t May be even lower. In some embodiments, signal s _t May be less than 50 μw or even less than 10 μw.

Accordingly, certain embodiments also provide an integrated sensor circuit comprising a transceiver circuit configured to transmit a radio signal having an electrical power of less than 100 μw (less than 50 μw or even less than 10 μw) towards a moving object and to receive a reflection of the radio signal from the moving object, and an evaluation circuit configured to determine a position and/or a velocity of the moving object based at least on the received radio signal.

As indicated in fig. 2, the movable part 210 and transceiver circuitry 220 of the machine may be arranged in a common shielded enclosure 240 to better isolate the device from the outside world. Thus, the pair/pair of signals s can be reduced or even completely eliminated _t And/or s _r Is a part of the electromagnetic interference. Conventional automotive radar systems for distance measurement are known to use radio frequencies, such as 77 GHz. In which the transceiver circuit 220 also employs the same radio In frequency embodiments, a shielded enclosure 240 covering both the mobile component 210 of the machine and the transceiver circuitry 220 may be useful for reducing interference to/from such conventional automotive ranging systems.

In some embodiments, the distance d between the at least one antenna 226 and the axis of movement of the movable member 210 will remain substantially unchanged. While the position of the transceiver circuitry 220 and/or the at least one antenna 226 may be fixed, the movable member 210 may be configured for linear (e.g., lateral) or rotational movement relative to the antenna 226 of the transceiver circuitry 220. Using the example of FIG. 2, movable member 210 may be moved laterally, for example, along x-axis 251 or rotated about y-axis 252. Note that block 210 is merely a placeholder for various movable components having different possible geometries.

For example, in some embodiments, the movable member 210 may be a rotatable movable object, such as a wheel, disk, or shaft (e.g., a crankshaft or camshaft). In this case, the evaluation circuit 230 may be configured to be based at least on the received radio signal s _r To determine the rotational position and/or rotational speed of movable member 210. For example, the evaluation circuit 230 may be configured to be based on the reflected signal s _r The change in power or amplitude of (a) to determine the position and/or velocity of movable element 210. Additionally or alternatively, the signal s may be used _t Sum s _r And a combination of both. For example, the evaluation circuit 230 may be configured to be based on the transmitted and reflected radio signals s _t Sum s _r The phase difference between them determines the position and/or velocity of movable element 210. In the latter case, an optional modulation of the transmitted signal may be helpful.

In certain embodiments, such as those associated with speed sensing, the movable member 210 may include a rotationally symmetrical cross-section in a plane perpendicular to the axis of rotation 252 of the movable member. In the example of fig. 2, this plane would be the x-z plane. In other embodiments, such as those related to angle sensing, the movable member 210 may include a rotationally asymmetric cross-section in a plane (e.g., the x-z plane) perpendicular to the axis of rotation 252 of the movable member. The difference between the minimum and maximum diameters may be significant for both rotationally symmetric or rotationally asymmetric cross sections. That is, the ratio between the smallest and largest diameter of the movable part in this plane may be less than 0.9.

Having explained certain general aspects of the present disclosure, we will now turn to some more specific examples.

Fig. 3 shows a transceiver circuit 320 having a transmit antenna 326-1 and a receive antenna 326-2 in close proximity (in some embodiments, less than 5cm or even less than 1 cm) to an encoder wheel or disk 310. In some embodiments, it may also be possible to use only a single antenna and a diplexer to separate the transmit and receive paths. The encoder wheel 310 has a rotationally symmetrical cross section in the x-z plane perpendicular to the axis of rotation (y-axis) of the movable member. Here, antennas 326-1, 326-2 are positioned radially outward from encoder wheel 310 such that radio signal s _t Is reflected by the annular outer skin surface of the movable member 310 extending parallel to the axis of rotation of the movable member.

The annular outer skin surface of the movable part comprises adjacent surface portions 312-1, 312-2, 312-3, 312-4 in the circumferential direction, which are configured for alternating electromagnetic reflectivity of radio signals emitted from the transceiver circuit 320. The first electromagnetic reflectivity of the radio signal of the first surface portion 312-1 is different from the second electromagnetic reflectivity of the radio signal of the adjacent second surface portion 312-2. This may be accomplished, for example, by using different surface materials for adjacent surface portions. For example, the first electromagnetic reflectivity may be obtained by metallization, while the second electromagnetic reflectivity may be obtained without metallization. Different electromagnetic reflectivities cause or generate different magnitudes of the corresponding received radio signals. The electromagnetic reflectivity of the radio signal of the third surface portion 312-3 adjacent to the second surface portion 312-2 may correspond to the first electromagnetic reflectivity of the first surface portion 312-1. The electromagnetic reflectivity of the radio signal of the fourth surface portion 312-4 adjacent to the third surface portion 312-3 may correspond to the second electromagnetic reflectivity of the second surface portion 312-2, and so on. In this way, a high and low value can be obtained when the wheel 310 rotates A periodically oscillating output signal 323. For example, a high output signal value may correspond to a surface portion 312 having a high electromagnetic reflectivity, while a low output signal value may correspond to a surface portion 312 having a low electromagnetic reflectivity. In certain embodiments, the first electromagnetic reflectivity may be substantially or significantly different from the second electromagnetic reflectivity, e.g., by at least 5% of the first or second electromagnetic reflectivity. That is, the ratio between the first electromagnetic reflectivity and the second electromagnetic reflectivity may be less than 0.95 (or greater than 1.05). For the received signal s _r And/or more pronounced amplitude oscillations of the output signal 323, the ratio between the first electromagnetic reflectivity and the second electromagnetic reflectivity may be, for example, less than 0.5 (or greater than 1.5).

In the example of fig. 3, radar IC 320 may measure received signal s reflected by structured target wheel 310 _r Amplitude modulation/variation of the power of (c). The amplitude variation is caused by a change in reflectivity between adjacent surface portions 312-1, 312-2, 312-3, 312-4. The alternating reflectivity may be caused, for example, by a metal coating on the plastic wheel. Those skilled in the art having the benefit of this disclosure will appreciate that various other options for alternating reflectivity are possible.

Fig. 4 illustrates a further exemplary embodiment in which adjacent surface portions of the movable component are configured to cause or generate different magnitudes of the received radio signal.

Fig. 4a shows an annular face of a movable member 410, such as a ring, disk or shaft. Similar to the embodiment of fig. 3, the annular face of the movable part comprises adjacent surface portions 412-1, 412-2, 412-3, 412-4 arranged in the circumferential direction, which are configured for alternating electromagnetic reflectivity of radio signals emitted from the transceiver circuit 420. In the example of fig. 4, transceiver circuitry 420 including antenna 426 is disposed in front of the annular face of the movable member. Based on the x, y, z coordinate system of fig. 3, a radio signal s is transmitted in the y-direction from the transceiver circuit 420 to the annular surface _t . At the same time, the rotation axis of the movable part also extends in the y-direction. However, there may be a radial offset between the rotational axis and the position of the transceiver circuitry 420. Thus, the disc 410 could also be used instead of a wheel, and would have an antennaIC 420 of 426 is placed in front of the disk.

Fig. 4b shows an annular face or cross section of the movable member 410', such as a toothed wheel or gear. The movable member 410' includes a plurality of teeth 412' -1 separated along its circumference by gaps 412' -2. The gear 410' has a rotationally symmetrical cross section in the x-z plane perpendicular to the axis of rotation (y-axis) of the movable part. Antenna 426 is positioned radially outward from gear 410' such that radio signal s _t Is reflected by the outer skin surface of the gear 410' extending parallel to the axis of rotation of the movable member. The teeth 412'-1 and the gaps 412' -2 of the skin surface of the gear provide adjacent surface portions in the circumferential direction, which are arranged at alternating distances from the rotational axis of the wheel. This also results in alternating (shortest) distances between each adjacent surface portion 412'-1, 412' -2 and the antenna 426 of the transceiver circuit 420. That is, the shortest distance (first distance) between the first surface portion 412' -1 of the movable member 410' and the antenna 426 of the transceiver circuitry 420 may be different from the shortest distance (second distance) between the adjacent second surface portion 412' -2 of the movable member and the antenna 426 of the transceiver circuitry 420. The skilled artisan will appreciate that the first and second distances may refer to the distances at which the teeth 412'-1 or gaps 412' -2, respectively, in fig. 4b directly face the one or more antennas 426. In the example depiction of fig. 4a, the tooth faces are opposite one or more antennas 426.

In some embodiments, the first distance may differ from the second distance by more than 5% of the first or second distance. That is, the ratio between the first distance and the second distance may be less than 0.95 (or greater than 1.05). For the received signal s _r The ratio between the first distance and the second distance may be, for example, less than 0.5 (or greater than 1.5). Note that adjacent radially offset surface portions 412' -1 and 412' -2 of movable member 410' may have the same electromagnetic reflectivity. Alternatively, however, it may have a different electromagnetic reflectivity in order to further enhance the variation of the reflected signal.

Thus, in some embodiments, a toothed wheel may be used instead of a metal printed wheel, and modulation occurs due to a change in distance rather than a change in material reflectivity.

The embodiments may be combined in different ways. For example, by evaluating the phase shift between received signals of adjacent antennas, an antenna array with spatial distance may be used to detect the direction of rotation in addition to the speed. Thus, a transceiver circuit according to an embodiment may include an antenna array. The evaluation circuit may be further configured to determine the direction of rotation of the movable part based on a phase shift between received signals of different antenna elements of the antenna array. While the phase shift may have a certain sign for clockwise rotation, the phase shift may have an opposite sign in case of counter-clockwise rotation. In some embodiments, the antenna arrays may be multiplexed, e.g., each antenna may be used for transmission or reception. In some embodiments, the antenna may be integrated in a package or on a chip. In the latter case, it may be advantageous to switch to frequencies of 200GHz or more in order to reduce the antenna structure size. The ability to receive modulated data on a 200GHz carrier has been given with current CMOS communications ICs (the results of the arrangement described above are the same).

Those who benefit from the present disclosure will appreciate that radar principles more complex than evaluating the amplitude/power of a received reflected radar wave may also be used. For example, the distance to the reflecting object may be estimated, which is one of the classical radar measurements of pulsed radar or Frequency Modulated Continuous Wave (FMCW) radar. For measurements at the toothed wheel, continuous Wave (CW) radar may also be used with an evaluation of the doppler effect, which may deliver a velocity signal, because near the edge of the tooth, the surface of the target moves towards the radar sensor (positive velocity pulse) and near the edge of the gap, the surface of the target moves away from the sensor and delivers a negative velocity pulse. Thus, there are various alternatives utilizing different radar principles.

Fig. 7 illustrates an example of a reflected signal sr related to an example embodiment for speed sensing.

The up-signal process (upper signal course) 710 may be obtained, for example, by down-converting a received radar signal that has been reflected by a moving (e.g., rotating) movable part of an adjacent surface portion having a different reflectivity. Signal down-conversion from the RF domain, which may be performed in a radar IC, may result in potentially noisy analog or digital Intermediate Frequency (IF) or baseband radar signals 712 with varying amplitude and/or phase. Radar signal 712 may optionally be filtered for noise suppression or reduction. In the illustrated example, the portion of the radar signal having a higher amplitude may correspond to the portion of the movable part having a higher reflectivity, while the portion of the signal having a lower amplitude may correspond to the portion of the movable part having a lower reflectivity.

The signal process 720 in the lower part of fig. 7 depicts an example of a radar sensor output signal 722. For example, the output signal pulse 722 may be generated and sent toward the ECU whenever the amplitude of the radar signal 712 exceeds a predefined signal threshold thres. Thus, in the illustrated example, the rising signal edges and the predefined signal threshold are used to generate an output signal pulse resulting in a binary sensor output signal having levels 'high' and 'low'. Those skilled in the art having the benefit of this disclosure will appreciate that other methods of generating the sensor output signal are possible. For example, falling signal edges and/or zero crossings of signal 712 may also be used as triggers for outputting signal pulses.

In yet further embodiments, the signal process 710 may also represent a phase difference between the reference signal and the received radar signal. Different phase differences may indicate different times of flight of the radar signal and, thus, different portions of the moving (e.g., rotating) movable component. Also in such an example, the sensor output signal 722 may be generated or triggered based on detecting/extracting signal edges and/or threshold and/or zero crossings of the phase difference signal.

In some embodiments, the switching threshold used to trigger the sensor output signal pulses may also be adaptive. For example, the threshold may be adaptable to moving objects/components of different materials and/or shapes. For example, in some embodiments, the switching threshold(s) may be modified via a learning algorithm, and thus provide a (self) calibration and/or hysteresis concept. There may be different hysteresis concepts implemented in the radar sensor IC. One form of hysteresis used to suppress undesired switching caused by noise in the signal may be referred to as a hidden hysteresis. This means that one cannot observe hysteresis from outside. If the value of the switching threshold/level is unchanged, the sensor output is always switched at the same level. But inside the IC there may be two different levels, tightly above and below the switching level, which can be used to prepare the output. In other words, if the value of the received radar signal passes through the lower of this hysteresis levels, the output may be able to switch if the radar signal passes through the switching level. After this switching event, the output may be disabled until the value of the radar signal crosses one of the two hysteresis levels. If it passes the higher hysteresis level, the output may be again prepared and if the radar signal passes the switching level, the switching may be made. On the other hand, if after one switching event the radar signal does not reach the higher hysteresis level but will pass the lower hysteresis level again, the output may be allowed to switch so that teeth will not be lost.

In speed sensing applications, the occurrence of the output signal pulse 722 (e.g., a signal edge) may be synchronized with the movement of the moving object/component, e.g., the signal edge of the output signal may be synchronized with the occurrence of a structure of the object such as a reflective structure (e.g., a tooth or a particular radar reflective structure mounted on the object). In other words, the signal edge corresponds to a specific structure, such as the start of a tooth (offset), or the like. Thus, a number of output signal pulses over a time interval can be used to evaluate the speed of the moving part.

Other embodiments may additionally or alternatively employ analysis of frequency components present in the received/reflected radar signal. Analyzing the spectrum (such as, for example, spectral expansion) may also yield information about the speed of the moving parts. In some embodiments, analysis of the radar signal may be performed in the radar sensor (e.g., on the same chip) to determine rotational speed information. In some embodiments, instead of providing output signal pulses with edges synchronized with the edges of the output signal, the absolute value of the velocity determined at the radar sensor may be transmitted to the control unit, for example using a digital or analog communication interface.

Having described several example embodiments for speed sensing, we will now also describe the same examples relating to measuring position or rotation angle. The angle sensing may in embodiments comprise an explicit sensing of the rotation angle of the rotatable object, also referred to as absolute angle sensing. The absolute angle sensing provided in embodiments herein is capable of determining a unique angle of rotation of this object, e.g., an angle between 0 and 360 °, from measurements taken for a particular rotational position. In addition, the absolute angle sensor may also be capable of providing continuous angle information. In contrast to an incremental sensor, an absolute angle sensor need not rely on previously sensed or stored historical information (such as a previous count of angular increments relative to a reference indication) in order to provide absolute rotational position information. Thus, in certain embodiments, when the absolute angle sensor is powered on, it is able to report its rotational position without requiring any additional historical angle information. According to some embodiments, this may be achieved by providing the machine with a rotatable movable part having a rotationally asymmetric cross section in a plane perpendicular to the axis of rotation of the movable part. In some embodiments, there may be substantial rotational asymmetry. Thus, the ratio between the smallest and largest diameter of the movable part in this plane may be less than 0.9 or even less than 0.5. The transceiver circuitry is configured to transmit radio signals toward the movable component and to receive reflections of the radio signals from the movable component. The evaluation circuit is configured to determine a rotational position and/or a rotational speed of the movable part based at least on received radio signals reflected from the rotationally asymmetric movable part.

Fig. 5a shows an apparatus 500 comprising a transceiver circuit 520, the transceiver circuit 520 having a transmit antenna 526-1 and a receive antenna 526-2 in close proximity (in some embodiments, less than 5em or even less than 1 em) to a movable member 510, the movable member 510 having an asymmetric cross section in a plane perpendicular to the axis of rotation 552 of the movable member. For example, the object 510 may be an axis of asymmetry (e.g., convexAxle or crankshaft). In the illustrated example, the cross-section of the movable member is elliptical. However, other rotationally asymmetric cross sections are also possible. Here, antennas 526-1, 526-2 are positioned radially outward from movable element 510 such that radio signal s _t Is reflected by the outer skin surface of the movable member 510 extending parallel to the axis of rotation of the movable member.

As indicated in the example of fig. 5a, the distance d between the antennas 526-1 and 526-2 and the skin surface is related to the rotation angle α of the movable object 510. In a position in which the major half axis of the elliptical movable object 510 is parallel to the z-direction (α=0), the distance d corresponds to the shortest distance between the antennas 526-1 and 526-2 and the skin surface of the movable object 510. In this position, the transceiver circuitry 520 will detect the maximum amplitude of the reflected signal. In a position in which the major half axis of the elliptical movable object 510 is parallel to the x-direction (α=pi/2), the distance d corresponds to the maximum distance between the antennas 526-1 and 526-2 and the skin surface of the movable object 510. In this position, the transceiver circuitry 520 will detect a minimum amplitude of the reflected signal. In another position, where the major half axis of the elliptical movable object 510 is anti-parallel to the z-direction (α=pi), the distance d again corresponds to the maximum distance between the antennas 526-1 and 526-2 and the skin surface of the movable object 510. In this position, the transceiver circuitry 520 will again detect the maximum amplitude of the reflected signal, and so on. Thus, it is possible to detect 180 ° explicit angle information based on the amplitude or power of the reflected signal. Alternatively or additionally, it is also possible to detect the frequency of the amplitude variation of the oscillating reflected signal. This frequency indicates the rotational speed ω of the movable object 510. The higher the frequency, the higher the rotational speed ω.

Fig. 5b illustrates an example of additionally or alternatively applying the doppler effect to its measurements.

In a position in which the major half axis of the elliptical movable object 510 is parallel to the z-direction (α=0), the distance d corresponds to the shortest distance between the antenna 526 and the skin surface of the movable object 510. Further, the rotational speed component in the z direction is 0. Thus, there will be no Doppler shifted received signal in this location. In the subsequent position in which the minor axis of the elliptical movable object 510 is parallel to the z-direction (α=pi/4), the rotational velocity component in the z-direction is the largest. Thus, there will be a maximum Doppler shifted received signal in this location. The higher the absolute value of the maximum doppler frequency, the higher the rotational speed ω of the moving object 510. In a subsequent position, in which the major half axis of the oblong movable object 510 is parallel to the x-direction (α=pi/2), the distance d corresponds to the maximum distance between the antenna 526 and the skin surface. In this position, the rotational speed component in the z direction is again 0. Thus, there will be no Doppler shifted received signal in this location. In the subsequent position, in which the minor axis of the elliptical movable object 510 is parallel to the x-direction (α=3/4pi), the absolute value of the rotational velocity component in the z-direction is again maximum, however with a different sign. Thus, there will be a maximum doppler shifted (with different symbols) received signal in this location.

As can be seen from the example shown in fig. 5c, the shape of the rotating object may also be asymmetric, like that of the drawing. In the example of fig. 5c, the rotational asymmetry is clear compared to the examples of fig. 5a, 5 b. That means that there may not be an axis of symmetry for the movable object 510'. In this case, the distance d can be directly converted into a 360 ° definite rotation angle α. Further, the speed signal is directly proportional to the rotational speed ω, and its sign indicates the rotational direction.

As indicated in fig. 5c, the radar sensor may also use an array of antennas 526 to form a directional antenna characteristic. Furthermore, it may use different antenna characteristics, such as-10 °, 0 ° and +10°, in order to simultaneously observe different points on the target 510', which for example would allow: the hold speed and position measurements are continuously made while the discontinuity 514 of the target 510' is present in the focus of one of the focus directions.

It will be appreciated that the illustrated example relating to measuring position or angle of rotation may measure angle continuously and/or absolutely due to the geometric shaping (rotational asymmetry) of the movable component.

Those skilled in the art who have the benefit of this disclosure will appreciate that a radar sensor according to an embodiment may additionally or alternatively measure the distance or speed to a linearly moving object (e.g., the bottom surface of a piston in an internal combustion engine). That is, the embodiment is limited not only to the detection of the rotational movement of the movable member but also to the detection of the linear movement of the movable member.

In summary, embodiments implement methods for position and/or velocity sensing that replace the magnetic sensor concept. A high-level flow chart of a method 600 is shown in fig. 6.

The method 600 includes moving 610 an object (linearly and/or rotationally) relative to at least one antenna of a transceiver, wherein a distance between the antenna and the moving object is (and remains) less than 5cm. The method 600 further includes transmitting 620 a radio signal from the transceiver towards the active object and receiving 630 a reflection of the radio signal from the active object at the transceiver. In act 640, a position and/or velocity of the object is determined based at least on the received radio signals.

Embodiments of the present disclosure may be employed in many industrial fields and particularly in automotive electronics where there is a need to measure the rotational speed of rotating components/wheels (e.g., ABS sensors, motor management, etc.). Embodiments may alternatively or additionally be used for semiconductor devices that are sensitive to magnetic fields (e.g., hall sensors; GMR sensors, etc.). In the latter case, small magnets attached to or in the vicinity of the rotating object must be used in addition to the magnetic sensor device. Further, the magnetic sensor must be positioned very close to the rotating object because its sensitivity decreases very rapidly with distance from the magnetic field source. The maximum allowable distance is typically in the millimeter range. Modern semiconductor technology enables the construction of small-sized monolithic radar transceivers (< 1 cm) capable of delivering radar waves and sensing small amplitude variations and/or phase/frequency shifts in the reflected radar signals ³ ) It becomes possible. The present disclosure proposes to use such a sensor for measuring the rotational speed of any rotating component in close proximity of a few centimeters from the sensor. Thus, the distance to the rotating object may be significantly larger (at least in cm range). Further, it is unnecessary to be expensiveExpensive and cumbersome magnets.

The description and drawings merely illustrate the principles of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the disclosure. Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the concepts contributed by the inventor(s) to furthering the art, and the principles of the disclosure, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass equivalents thereof.

It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudocode, and the like represent various processes which may be substantially represented in computer readable media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

Furthermore, the following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate example embodiment. Although each claim may stand alone as a separate example embodiment, it is noted that although a dependent claim may refer in the claims to a specific combination with one or more other claims, other example embodiments may also include combinations of the dependent claim with the subject matter of each other dependent or independent claim. Such combinations are presented herein unless a specific combination is not intended to be stated. Furthermore, the features of a claim are intended to be included in any other independent claim even if such claim is not directly dependent on that independent claim.

It is also noted that the methods disclosed in the specification or in the claims may be implemented by a device having means for performing each of the respective actions of the methods.

Furthermore, it is to be understood that the disclosure of various actions or functions disclosed in the specification or claims may not be construed as being within the specific order. Thus, the disclosure of multiple acts or functions will not limit these to a particular order unless such acts or functions are not interchangeable for technical reasons. Further, in some embodiments, a single action may include multiple sub-actions or may be broken up into multiple sub-actions. Unless expressly excluded, such sub-actions may be included and are part of the disclosure of this single action.

Claims

1. A machine, comprising:

a movable member;

transceiver circuitry configured to transmit radio signals towards the movable component and to receive reflections of radio signals from the movable component;

an evaluation circuit configured to determine a rotational position of the movable part based on a received reflection of the radio signal,

wherein the movable part comprises a rotationally asymmetric characteristic to continuously and/or absolutely measure the rotational position.

2. The machine of claim 1, wherein the movable member comprises a rotationally asymmetric cross section in a plane perpendicular to an axis of rotation of the movable member.

3. The machine of claim 2, wherein a ratio between a minimum and a maximum diameter of the movable member in the plane is less than 0.9.

4. The machine of claim 1, wherein adjacent surface portions of the movable component are configured to alternate electromagnetic reflectivity of radio signals.

5. The machine of claim 4, wherein a first electromagnetic reflectivity of a radio signal of a first surface portion of the movable member is different from a second electromagnetic reflectivity of a radio signal of an adjacent second surface portion of the movable member.

6. The machine of claim 5, wherein the first electromagnetic reflectivity differs from the second electromagnetic reflectivity by more than 5% of the first or second electromagnetic reflectivity.

7. The machine of claim 1, wherein the transceiver circuitry is configured to transmit a radio signal having an electrical power of less than 100 μw.

8. The machine of claim 1, wherein the transceiver circuit comprises an antenna array, and wherein the evaluation circuit is further configured to determine the direction of rotation of the movable component based on a combination of received signals of different antennas of the antenna array.

9. The machine of claim 8, wherein a shortest distance between a first surface portion of the movable component and an antenna of the transceiver circuit is different than a shortest distance between an adjacent second surface portion of the movable component and an antenna of the transceiver circuit.

10. The machine of claim 9, wherein a shortest distance between the first surface portion and the antenna differs from a shortest distance between the adjacent second surface portion and the antenna by more than 5%.

11. The machine of claim 8, wherein a distance between an antenna of the transceiver circuit and the movable member is less than 5cm.

12. The machine of claim 1, wherein the transceiver circuit and the evaluation circuit are integrated in a common semiconductor package or chip.

13. The machine of claim 1, wherein the movable component and the transceiver circuitry are commonly disposed in a shielded enclosure.

14. The machine of claim 1, wherein the movable member is a wheel, a disc, or a shaft.

15. The machine of claim 1, wherein the machine is a vehicle.